The present invention relates to an apparatus for creating gas pressure and/or flow cycles and has an important application, although not exclusive, in testing units which, in operation, are subjected to pressure and flow cycles such as breathing systems or regulators.
At the present time, breathing systems are checked and tested with apparatuses where the operating conditions are manually adjusted. Such tests are long and do not permit a sufficient variety of operating cycles to be simulated.
It is an object of the invention to provide an apparatus for creating reproducible cycles of a wide variety and for applying them to units placed in any environment, particularly altimetric or pressurized environments.
According to the invention, there is provided an apparatus for creating predetermined gas flow cycles, comprising:
a housing limiting an inner chamber provided with a gas flow opening, PA0 a movable unit having a throttling member cooperating with said opening for defining a passage having a cross-sectional flow area depending on the position of said movable unit, PA0 electrically actuatable valve means for communicating said chamber to either of a plurality of gas sources at predetermined different pressures, PA0 electrical motor-means for controlling the position of said movable unit, and PA0 electrical sensor means operatively associated with said movable unit to deliver an electric signal representative of the location of said unit in the housing.
One of the gas pressure sources may be a vacuum pump; it may also be a pressurized gas source, one or more pressure reducers supplying a constant but adjustable pressure being placed between the pressurized gas source and the solenoid valve.
Operation of the apparatus will preferably be controlled by a control and data processing unit which will typically be digital and include a CPU which may be a microprocessor. The CPU or central processing unit will receive the signals from position-detecting electromagnetic sensor means and possibly from pressure sensors provided on the apparatus or the unit to be tested.
A particularly interesting application of the invention is for testing breathing units. The unit will thus be generally placed in a sealed box where an air pressure different from the normal atmospheric pressure may be provided, for example less than atmospheric pressure (in the case of breathing equipment for aircraft crews) or higher than atmospheric pressure (in the case particularly of diving equipment).
The apparatus is also suitable for use in the medical field for simulating respiratory cycles which may have been measured when a patient is in satisfactory conditions and then applying said cycles to a patient during abnormal conditions, for instance during a surgical operation; it may also provide assistance in emphysema.
The invention will be better understood from the following description of a particular embodiment, given by way of example. The description refers to the accompanying drawings.